Jango >>> Boba. Jango was able to stand up to Obi-Wan in both a ranged duel and fist fight despite it being established in both continuities that Force users can amplify their physical capabilities (eg. Obi-Wan not breaking any bones from taking a hit from Grievous that was shown capable of denting a fighter-class ship), got the better of and killed a High-Council member and had a lot of other boss feats in Legends. Meanwhile, Boba got quickly put on the losing end by a Luke still inexperienced enough to get his hand injured by a blaster in battle and was lacking in his awareness enough to job to a blind Han Solo.
Now, I haven't seen what The Mandalorian is capable of beyond clips and episode summaries (because to hell with shilling to The Mouse), but they don't seem to be up to scratch to what Jango's capable of beyond having more unconventional tactics. Those would probably give Jango trouble in the right environment, but still not measure up to his experience and gunplay. Someone like Pre Visla would probably be a better match for Jango.